Deformation-Induced Surface Roughening of an Aluminum-Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

Yannis P Korkolis; Paul Knysh; Kanta Sasaki; Tsuyoshi Furushima; Marko Knezevic

doi:10.3390/ma16165601

Deformation-Induced Surface Roughening of an Aluminum-Magnesium Alloy: Experimental Characterization and Crystal Plasticity Modeling

Materials (Basel). 2023 Aug 12;16(16):5601. doi: 10.3390/ma16165601.

Authors

Yannis P Korkolis¹, Paul Knysh², Kanta Sasaki³, Tsuyoshi Furushima⁴, Marko Knezevic²

Affiliations

¹ Department of Integrated Systems Engineering, The Ohio State University, 234 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA.
² Department of Mechanical Engineering, University of New Hampshire, 33 Academic Way, Durham, NH 03824, USA.
³ Department of Mechanical Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan.
⁴ Institute of Industrial Science, University of Tokyo, Komaba 4-6-1, Meguro, Tokyo 153-8505, Japan.

Abstract

The deformation-induced surface roughening of an Al-Mg alloy is analyzed using a combination of experiments and modeling. A mesoscale oligocrystal of AA5052-O, obtained by recrystallization annealing and subsequent thickness reduction by machining, that contains approx. 40 grains is subjected to uniaxial tension. The specimen contains one layer of grains through the thickness. A laser confocal microscope is used to measure the surface topography of the deformed specimen. A finite element model with realistic (non-columnar) shapes of the grains based on a pair of Electron Back-Scatter Diffraction (EBSD) scans of a given specimen is constructed using a custom-developed shape interpolation procedure. A Crystal Plasticity Finite Element (CPFE) framework is then applied to the voxel model of the tension test of the oligocrystal. The unknown material parameters are determined inversely using an efficient, custom-built optimizer. Predictions of the deformed shape of the specimen, surface topography, evolution of the average roughness with straining and texture evolution are compared to experiments. The model reproduces the averaged features of the problem, while missing some local details. As an additional verification of the CPFE model, the statistics of surface roughening are analyzed by simulating uniaxial tension of an AA5052-O polycrystal and comparing it to experiments. The averaged predictions are found to be in good agreement with the experimentally observed trends. Finally, using the same polycrystalline specimen, texture-morphology relations are discovered, using a symbolic Monte Carlo approach. Simple relations between the Schmid factor and roughness can be inferred purely from the experiments. Novelties of this work include: realistic 3D shapes of the grains; efficient and accurate identification of material parameters instead of manual tuning; a fully analytical Jacobian for the crystal plasticity model with quadratic convergence; novel texture-morphology relations for polycrystal.

Keywords: aluminum; crystal plasticity; oligocrystal; polycrystal; surface roughening.

Grants and funding

This research was supported by NSF award CMMI-1150523, which also supported a research stay by PK at the Institute of Industrial Science, University of Tokyo, in the summer of 2017. This support is acknowledged with thanks. The visit was also supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (c) Grant Number JP 16K06800.